Method for separating and purifying polyhydroxyalkanoate from interiors of microbial cells

Abstract

The invention provides a method for separating and purifying polyhydroxyalkanoate from the interiors of microbial cells. The method includes the following steps: after a microbial strain producing polyhydroxyalkanoate is fermented, the bacterial cells in fermentation broth are collected; in an ultrasonic generator, the bacterial cells are mixed with organic solvent, the dosage of the organic solvent is 10 to 30 times as much as the bacterial cells, and after 20 to 70 minutes of ultrasonic vibration under 40 DEG C to 80 DEG C, solid-liquid mixture is obtained; the solid-liquid mixture is separated centrifugally or by filtration, so that a liquid phase containing polyhydroxyalkanoate is obtained; the liquid phase containing polyhydroxyalkanoate is cooled to 0 DEG C to 10 DEG C, the temperature is kept for 10 to 30 minutes, so that turbid liquid which is formed after polyhydroxyalkanoate crystals are separated out is obtained; the turbid liquid is separated centrifugally or by filtration, so that solid polyhydroxyalkanoate is obtained; and after the solid polyhydroxyalkanoate is dried, finished polyhydroxyalkanoate product is obtained. The method has the advantages of simple process, low energy consumption, low production cost and high product extraction rate, and is easy to operate.

Description

technical field [0001] The invention relates to the technical field of separation and purification of downstream products of bioengineering, in particular to a method for separating and purifying polyhydroxyalkanoate from microbial cells. Background technique [0002] Polyhydroxyalkanoate (Polyhydroxyalkanoate, PHAs) is a biopolymer material that has been developed rapidly in the past two decades. It plays an important role in environmental protection and medical applications. It has become a direction for the production, development and application of new materials. It is one of the most active hotspots in the field of biomaterials. Polyhydroxyalkanoate is a type of intracellular thermoplastic polyester synthesized by microorganisms to store excess carbon sources in the form of carbon sources and energy sources, and the cumulative amount can account for 30% - 80% of the dry weight of cells. For PHAs, when the number of carbon atoms in the polymerized monomer is 3-5, the re...

AI Technical Summary

Problems solved by technology

The use of chemical reagents to treat cells usually requires a reaction at a higher temperature, which often causes the degradation of the product PHAs and affects the application performance of the product

The solvent extraction process usually requires a large amount of solvent, involves solvent evaporation and concentration, solvent condensation, recovery and reuse, and the whole process consumes a lot of energy.

In addition, when about 5% of PHAs are dissolved in organic solvents, the viscosity of the solvent will increase, which will affect the extraction rate of the separation process and the purity of the separated products.